Operation method of sidelink relay, and sidelink relay therefor

1 . An operation method of a first terminal for establishing a relay connection, the operation method comprising:

generating a PC5-relay adaptation layer (PC5-RAL) protocol data unit (PDU) header for the first terminal, the PC5-RAL PDU header including or not including a remote terminal identifier and a connection identifier;

mapping the generated PC5-RAL PDU header to a PC5-radio link control (RLC) channel; and

generating a PC5-RAL PDU by adding data to the PC5-RAL PDU header, and transmitting the generated PC5-RAL PDU to a corresponding second terminal through the PC5-RLC channel,

wherein the first terminal is a remote terminal, and the second terminal is a relay terminal,

wherein a first PC5-RAL is located above a PC5-RLC layer of the first terminal, and a second PC5-RAL is located above a PC5-RLC layer of the second terminal,

wherein the first terminal configures, for a relay-Uu-radio resource control (R-Uu-RRC) message which is a signaling message, the PC5-RAL PDU using the PC5-RAL PDU header not including the remote terminal identifier and the connection identifier, or configures the PC5-RAL PDU using the PC5-RAL PDU header including the remote terminal identifier and the connection identifier, and

wherein the first terminal configures, for a relay-Uu-service data adaptation protocol (R-Uu-SDAP) message for transferring user data, the PC5-RAL PDU by using the PC5-RAL PDU header including the remote terminal identifier and the connection identifier.

2 . The operation method according to claim 1 , wherein the remote terminal identifier is a local remote terminal identifier determined by a base station and delivered to the first terminal or the second terminal.

3 . The operation method according to claim 1 , wherein the first terminal determines the PC5-RLC channel mapped to the remote terminal identifier and the connection identifier, or the first terminal determines the PC5-RLC channel mapped to the connection identifier.

4 . The operation method according to claim 1 , wherein the first terminal determines a PC5-layer 2 (L2) identifier mapped to the remote terminal identifier.

5 . The operation method according to claim 1 , further comprising activating the first PC5-RAL in the first terminal or the second PC5-RAL in the second terminal, wherein the remote terminal identifier and the connection identifier are configured in the activating of the first PC5-RAL or the second PC5-RAL.

6 . An operation method of a relay terminal for establishing a relay connection, the operation method comprising:

identifying a remote terminal identifier and a connection identifier in a first relay adaptation layer (RAL);

generating, in a second RAL, an RAL protocol data unit (PDU) header including or not including the remote terminal identifier and the connection identifier;

mapping the generated RAL PDU header to a radio link control (RLC) channel; and

adding data to the RAL PDU header of the second RAL to generate an RAL PDU of the second RAL, and transmitting the generated RAL PDU to a corresponding communication node through the RLC channel,

wherein the first RAL is a PC5-RAL located above a PC5-RLC layer or a Uu-RAL located above a Uu-RLC layer, the second RAL is a Uu-RAL above the Uu-RLC layer or a PC5-RAL above the PC5-RLC layer, and the communication node is a remote terminal or a base station,

wherein the relay terminal configures, for a relay-Uu-radio resource control (R-Uu-RRC) message which is a signaling message, the RAL PDU using the RAL PDU header not including the remote terminal identifier and the connection identifier, or configures the RAL PDU using the RAL PDU header including the remote terminal identifier and the connection identifier, and

wherein the relay terminal configures, for a relay-Uu-service data adaptation protocol (R-Uu-SDAP) message for transferring user data, the RAL PDU using the RAL PDU header including the remote terminal identifier and the connection identifier.

7 . The operation method according to claim 6 , wherein the first RAL identifies the remote terminal identifier and the connection identifier from a received RAL PDU header.

8 . The operation method according to claim 6 , wherein the first RAL identifies the remote terminal identifier and the connection identifier associated with an RLC channel through which a received RAL PDU is transmitted.

9 . The operation method according to claim 6 , wherein an RAL PDU header received in the first RAL is delivered to the second RAL, and the second RAL generates the RAL PDU of the second RAL by using the received RAL PDU header identically.

10 . The operation method according to claim 6 , further comprising activating the first RAL and the second RAL in the relay terminal, wherein the remote terminal identifier and the connection identifier are configured in the activating of the first RAL and the second RAL.

11 . The operation method according to claim 6 , further comprising:

extracting, by the first RAL, data by removing an RAL PDU header from a received RAL PDU;

delivering, by the first RAL, the data to the second RAL; and

generating, by the second RAL, an RAL PDU only with the data, or generating, by the second RAL, an RAL PDU with the data and an RAL PDU header including the remote terminal identifier and the connection identifier.